Vibrational branching ratios in the (b(2u))(-1) photoionization of C6F6.
ABSTRACT The vibrational branching ratios in the photoionization of C(6)F(6) leading to the C (2)B(2u) state of C(6)F(6)(+) are considered. Computational and experimental data are compared for the excitation of two totally symmetric modes. Resonant features at photon energies near 19 and 21 eV are found. A detailed analysis of the computed results shows that the two resonance states have different responses to changes in the C-C and C-F bond lengths. We find that the energies of both of the resonant states decrease with increasing bond lengths. In contrast to the energy positions, however, the resonant widths and the integrated oscillator strength of the resonances can either increase or decrease with increasing bond length depending on the nature and location of the resonant state and the location of the bond under consideration. With increasing C-F bond length, we find that the energy of the antibonding sigma resonance localized on the ring has a decreasing resonance energy and also a decreasing lifetime. This behavior is in contrast to the usual behavior of shape resonance energies where increasing a bond length leads to decreasing resonance energies and increasing resonance lifetimes. Finally, for the first time, we examine the effect of simultaneously occurring multiple vibrations on the resonance profile for valence photoionization, and we find that the inclusion of more than a single vibrational mode substantially attenuates the strength of resonance.
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ABSTRACT: Evidence is presented demonstrating that an electron launched into the continuum is trapped in an unprecedented quasibound state, namely, one that extends through the backbone of the six-member carbon ring of C6F6. The mode specificity of the vibrational sensitivity to the electron trapping provides an experimental signature for this phenomenon, while adiabatic static model-exchange scattering calculations are used to map the wave function, which corroborate the interpretation.The Journal of Chemical Physics 11/2006; 125(16):164316. · 3.16 Impact Factor